With Viscount Monckton of Brenchley currently touring New Zealand, I expect many of his adherents – including Federated Farmers, will hear quite a bit about the end of climate change because world temperatures haven’t increased for a decade. This meme is taking hold in all the places that want to latch hold of a headline rather than read the whole article (see post about Rodney Hide below). The Economist has recently posted a short discussion with their ‘Globalisation Editor’ in which he calls for a roll-back of climate measures in light of the mounting evidence.
Why then has the last decade – the warmest on record, not continued to get warmer as record amounts of CO2 are pumped into the atmosphere?
- The historic temperature record doesn’t show a steady year-by-year increase; there is typically a step-wise progression with plateaus followed by sharp jumps i.e a staircase rather than and single slope. A plateau in the temperature record is not in itself surprising.
- The El Nino – La Nina cycle has an impact on global temperatures with El Nino dominated years relatively warm and La Nina years relatively cool. If the recent temperature record is divided into El Nino, La Nina and intermediate years and plotted, each category shows a near identical rise in temperature that has not paused nor shown evidence of decline.
- It is also apparent that man-made forces might be counteracting the expected temperature increases. Recently analysis has implicated pollution through both the input of aerosols into the atmosphere (think Beijing) that reflect incoming energy from the sun and fertilisation of the biosphere via CO2 and nitrogen that promote plant growth and the uptake of CO2. The question is are we prepared endure current levels of pollution to defer temperature rise?
Finally new research has revealed that although the surface temperature record has been static, in fact overall global warming has accelerated with more heat now being taken up by the oceans.
Overall this is a good example of how science works. We make an observation that temperatures have been static for a while and either go yippee the panic is over, or we say that’s funny, everything we know about physics says it should still be warming, what could be the reason? A variety of mechanisms have been proposed that may individually or collectively explain the phenomenon – none offer a reason to relax.